Mattress with substantially uniform fire resistance characteristic

ABSTRACT

A fire resistant (FR) mattress comprising a core comprising a first densified nonwoven fiber batt, and a ticking comprising a first fabric, the ticking enclosing the core and the fill layer, wherein the core and the ticking consist essentially of a common fiber composition having substantially identical FR characteristic, thereby imparting the substantially uniform FR characteristic upon the mattress. In another aspect, the invention includes a mattress comprising a core, a plurality of substantially adjacent similarly oriented spring coils arranged in a common plane within the core, and a ticking comprising a first fabric, the ticking enclosing the core and the fill layer, wherein the core and the ticking consist essentially of a common fiber composition having substantially identical FR characteristic, thereby imparting the substantially uniform FR characteristic upon the mattress.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

A mattress typically comprises a mattress core and a plurality of fill layers encased in a decorative ticking. The mattress core contains a plurality of springs and other optional components such as foam, and high-loft and densified nonwoven fiber batts. The fill layers contain a plurality of cushioning components such as foam and high-loft nonwoven fiber batts. The foam and high-loft fiber batts provide softness and comfort for a person sleeping on the mattress, while the springs and densified fiber batts provide firmness and support for the person sleeping on the mattress. In order to keep the springs from penetrating the other layers of the mattress core, a densified fiber batt, known as an insulator pad, is positioned between the springs and the other mattress components. The insulator pad is sufficiently dense such that it cannot be penetrated by the wire that makes up the mattress springs. The core, the fill layers, and the insulator pad are typically encased within a fabric ticking. If desired, a quilted layer of material may be added on top of the fill layer in order to give the mattress additional softness.

One problem associated with conventional mattress designs is that the mattresses are flammable. Mattress fires are dangerous because the combustible mattress components, such as the ticking and the fill layer, burn rapidly when ignited. The heat from the fire also heats the compressed mattress springs in the core, causing them to expand. As the mattress fire consumes the insulator pad, the insulator pad weakens and is unable to maintain the separation between the springs and the other combustible mattress components. Consequently, the springs penetrate the insulator pad and push the mattress components into the fire, infusing the fire with fresh fuel. Because the springs are wound in a helical pattern with air in the center, when the springs expand into the fire, they also infuse the fire with fresh oxygen. The combination of flammable fabrics, foams, and compressed mattress springs allow mattress fires to reach temperatures in excess of 1000° F., making them one of the most dangerous types of household fires. Realizing the magnitude of the danger associated with mattress fires, almost every mattress manufacturer in the United States has developed, or is developing, mattresses with fire resistant (FR) properties.

An important part of an FR mattress design is the location of the layer of FR material (the FR layer) within the mattress. Existing FR mattress designs locate the FR layer at or near the surface of the mattress. For example, some products incorporate the FR layer into the mattress ticking, while other products position the FR layer directly underneath the mattress ticking. The fundamental concept behind these products is the creation of a FR layer between the fire and most or all of the combustible mattress components, thereby separating the fire from a potential fuel source.

Locating the FR layer at or near the surface of the mattress limits the effectiveness of the FR layer. Being located at or near the surface of the mattress, the FR layer is limited to soft and flexible materials because the use of hard or rigid materials at or near the surface of the mattress makes the mattress uncomfortable to sleep on. In order for the FR layer to be soft and flexible, however, the structural integrity of the FR layer must be decreased. The decrease in structural integrity makes the FR layer susceptible to fracture or breakage, particularly during a fire. If the FR layer fractures or breaks during a fire, the FR layer is no longer able to maintain the separation between the fire and the combustible mattress components. Without this separation, the fire consumes the combustible mattress components and heats the compressed mattress springs causing them to expand and penetrate the insulator pad, the fill layers, and the FR layer, further propagating the mattress fire. Thus, the failure of any part of the FR layer eventually leads to propagation of the mattress fire as if there were no FR layer. The FR characteristics of the mattress would be improved if the entire mattress were constructed of FR materials such that failure of a part of the surface FR layer would not allow the springs to propagate the fire. Consequently, a need exists for a mattress comprising entirely FR materials such that the failure of any of the mattress components during a mattress fire will not lead to propagation of the mattress fire.

Some mattress manufacturers have attempted to use fiberglass as an FR material in mattresses. However, fiberglass has a tendency to produce glass shards capable of irritating the skin. More specifically, when a FR mattress includes fiberglass, the fiberglass tends to fracture into glass shards when exposed to repeated bending stresses such as those which are produced by a person rolling around in or sitting on the side of a bed. When the fiberglass fractures, the resultant glass shards are capable of migrating through the mattress and bed sheets to the surface of the mattress. Once on the surface of the mattress, the glass shards may become embedded in the skin of a person sleeping or otherwise resting on the mattress, thereby causing that person to itch. The discomfort resulting from use of the FR mattress typically overrides any perceived need for protection from fire, thereby resulting in non-acceptance of the fiberglass FR mattresses within the industry and by the consumer. Therefore, a need exists for an FR mattress that is free of fiberglass such that the mattress will be accepted by the mattress industry and the consumers.

SUMMARY

In one aspect, the invention includes a FR mattress comprising: a core comprising a first densified nonwoven fiber batt; and a ticking comprising a first fabric, the ticking enclosing the core and the fill layer; wherein the core and the ticking consist essentially of a common fiber composition having substantially identical FR characteristic, thereby imparting the substantially uniform FR characteristic upon the mattress. In an embodiment, the mattress of claim further comprises a fill layer comprising a first high-loft nonwoven fiber batt, the fill layer positioned between the core and the ticking; and wherein the core, the fill layer, and the ticking consist essentially of a common fiber composition having substantially identical FR characteristic, thereby imparting the substantially uniform FR characteristic upon the mattress. In embodiments, the common fiber composition consists essentially of synthetic fibers, the mattress further comprises a plurality of similarly oriented spring coils arranged in a common plane within the core, a coil spring path is adjacent to each of the spring coils in the core, and/or the mattress further comprises an insulator pad comprised of a second densified nonwoven fiber batt consisting essentially of the common fiber composition, the insulator pad positioned between the core and the fill layer such that the insulator pad separates the core from the fill layer. In another embodiment, the mattress further comprises: a quilt panel positioned above the fill layer, the quilt panel comprising: a quilt backing comprised a second fabric consisting essentially of the common fiber composition; and a quilt layer comprised a second high-loft nonwoven fiber batt consisting essentially of the common fiber composition. In yet another embodiment, the mattress further comprises: a tape comprised of a third fabric consisting essentially of the common fiber composition; and a thread comprising at least one filament consisting essentially of the common fiber composition; wherein the tape and the thread join the edges of the ticking together, thereby creating a seam. Variously, the core, the insulator pad, the fill layer, the ticking, the quilt panel, the tape, and the thread are fire resistant, the core, the insulator pad, the fill layer, the ticking, the quilt panel, the tape, and the thread are substantially free of fiberglass, and/or the common fiber composition consists essentially of fibers selected from the group consisting of: polyester and polypropylene.

In another aspect, the invention includes a mattress comprising: a core; a plurality of substantially adjacent similarly oriented spring coils arranged in a common plane within the core; and a ticking comprising a first fabric, the ticking enclosing the core and the fill layer; wherein the core and the ticking consist essentially of a common fiber composition having substantially identical FR characteristic, thereby imparting the substantially uniform FR characteristic upon the mattress. In an embodiment, the mattress of further comprises: a fill layer comprising a first high-loft nonwoven fiber batt, the fill layer positioned between the core and the ticking; and wherein the core, the fill layer, and the ticking consist essentially of a common fiber composition having substantially identical FR characteristic, thereby imparting the substantially uniform FR characteristic upon the mattress. In other embodiments, the common fiber composition consists essentially of synthetic fibers, the core further comprises a first densified nonwoven fiber batt, a coil spring path is adjacent to each of the spring coils in the core, and/or the mattress further comprises an insulator pad comprised of a second densified nonwoven fiber batt consisting essentially of the common fiber composition, the insulator pad positioned between the core and the fill layer such that the insulator pad separates the core from the fill layer. In another embodiment, the mattress further comprises a quilt panel positioned above the fill layer, the quilt panel comprising: a quilt backing comprised a second fabric consisting essentially of the common fiber composition; and a quilt layer comprised a second high-loft nonwoven fiber batt consisting essentially of the common fiber composition. In yet another embodiment the mattress further comprises a tape comprised of a third fabric consisting essentially of the common fiber composition; and a thread comprising at least one filament consisting essentially of the common fiber composition; wherein the tape and the thread join the edges of the ticking together, thereby creating a seam. Variously, the core, the insulator pad, the fill layer, the ticking, the quilt panel, the tape, and the thread are fire resistant, the core, the insulator pad, the fill layer, the ticking, the quilt panel, the tape, and the thread are substantially free of fiberglass, and/or the common fiber composition consists essentially of fibers selected from the group consisting of: polyester and polypropylene.

In yet another aspect, the invention includes a mattress comprising: a core; a plurality of substantially adjacent similarly oriented spring coils arranged in a common plane within the core; a fill layer comprising a first high-loft nonwoven fiber batt, the fill layer positioned above the core; an insulator pad comprised of a first densified nonwoven fiber batt, the insulator pad positioned between the core and the fill layer such that the insulator pad separates the core from the fill layer; a ticking comprising a first fabric, the ticking enclosing the core, the insulator pad, and the fill layer; a quilt panel positioned above the fill layer, the quilt panel comprising: a quilt backing comprised a second fabric; and a quilt layer comprised a second high-loft nonwoven fiber batt; a tape comprised of a third fabric consisting essentially of the common fiber composition; and a thread comprising at least one filament consisting essentially of the common fiber composition; wherein the tape and the thread join the edges of the ticking together, thereby creating a seam; and wherein the core, the fill layer, the insulator pad, the quilt backing, the quilt layer, the tape, the thread, and the ticking consist essentially of a common fiber composition having substantially identical FR characteristic, thereby imparting the substantially uniform FR characteristic upon the mattress. In embodiments, the common fiber composition consists essentially of synthetic fibers, the core further comprises a second densified nonwoven fiber batt consisting essentially of the common fiber composition, the core, the insulator pad, the fill layer, the ticking, the quilt panel, the tape, and the thread are fire resistant, the core, the insulator pad, the fill layer, the ticking, the quilt panel, the tape, and the thread are substantially free of fiberglass, and/or the common fiber composition consists essentially of fibers selected from the group consisting of: polyester and polypropylene.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and for further details and advantages thereof, reference is now made to the accompanying drawings, in which:

FIG. 1 is a cross-section view of an embodiment of the Mattress with Substantially Uniform Fire Resistance Characteristic;

FIG. 2 is a flow chart of an embodiment of a method for making the one of the high-loft nonwoven components of the Mattress with Substantially Uniform Fire Resistance Characteristic;

FIG. 3 is a top view of an example of an apparatus for implementing the method illustrated in FIG. 2;

FIG. 4A is a side view of the thermal bonding apparatus used in forming a nonwoven fiber batt;

FIG. 4B is a side view of an alternative thermal bonding apparatus used in forming a nonwoven fiber batt;

FIG. 5 is a flow chart of an embodiment of a method for making the one of the densified nonwoven components of the Mattress with Substantially Uniform Fire Resistance Characteristic; and

FIG. 6 is a top view of an example of an apparatus for implementing the method illustrated in FIG. 5.

DETAILED DESCRIPTION

In an embodiment, the invention is an FR mattress with a substantially uniform FR characteristic. The FR mattress has a substantially uniform FR characteristic because substantially all of the mattress components are made of the same material. Of all the mattress component materials available, nonwoven fiber batts are the preferred construction material because of their advantageous properties. First and foremost, nonwoven fiber batts exhibit superior FR properties when compared to foams, which are highly flammable. Nonwoven fiber batts also have superior air permeability and do not have toxic combustion byproducts. Specifically, nonwoven fiber batts of comparable thickness and density generally have about seventy-five percent better air permeability than comparable foams. The improved air permeability allows the fiber batt to circulate air throughout the mattress and distribute moisture, thereby minimizing mildew, mold, and odor associated with liquid spills on the fiber batt. In addition, the air permeability allows the fiber batt to circulate air to dissipate heat more efficiently than foams. Unlike polyurethane and other foams, the fiber batts do not produce toxic gases during combustion. Synthetic fibers are also hypo allergenic. Thus, nonwoven fiber batts possess superior characteristic when compared with other mattress construction materials, such as polyurethane foam.

Nonwoven fiber batts containing synthetic fibers or blends containing synthetic fibers are preferred for the mattress with substantially uniform FR characteristic. Synthetic fibers are preferred because they tend to melt and drip rather than burn when exposed to open flame. Synthetic fibers also tend to shrink away from heat sources in that they will self-compress and retreat from the direction of the heat source prior to melting and dripping. If ignited, the synthetic fiber batts self-extinguish such that the non-ignited portions of the fiber batt will retreat away from the burning portion of the fiber batt, leaving the fire insufficient fuel and thereby extinguishing the flame. The combination of the shrinking away action, melting, and dripping allows the synthetic fibers to resist combustion better than natural fibers. Although substantially all synthetic fibers posses the advantageous properties described herein, polyester is most preferred because it balances cost with the aforementioned shrinking away, melting, and dripping properties.

Regardless if the mattress is constructed of the same type of synthetic fiber or synthetic fiber blend, the mattress has a substantially uniform FR characteristic because all of the mattress components contain the same type of fiber or the same fiber blend. In having a substantially uniform FR characteristic, the mattress components are all equally FR such that if the mattress catches fire and the fire partially burns through one or more of the mattress components, the FR characteristic, e.g. the flammability, of the mattress does not change. For example, if the fire burns through the mattress ticking, an underlying quilt panel that becomes exposed to the fire is no more flammable than the ticking that the fire burned through. In contrast, when prior art FR mattresses caught fire and the fire burned through the insulator pad or FR layer, the FR characteristic of the mattress changed substantially because the flammable mattress components became exposed to the fire and the fire rapidly propagated after exposure to the flammable mattress components, particularly when the coiled springs in the core expanded after the insulator pad was consumed by the fire. The substantially uniform FR characteristic of the invention allows the mattress with substantially uniform FR characteristic to prevent dangerous mattress fires with greater efficiency than the prior art FR mattresses.

In addition to the improved FR properties, the substantially uniform composition of mattress allows it to have other advantageous benefits. Constructing a mattress out of a consistent type of fiber or fiber blend reduces the types of processes that the mattress manufacturer has to use to assemble the mattress. For example, if a mattress were made entirely out of nonwoven polyester batts, the mattress manufacturer would not have to possess the machinery associated with production, handling, or incorporation of foam into a mattress or concern itself with the particularities associated with processing other types of fibers, such as polypropylene. In addition, the utilization of a single type of fiber or fiber blend eliminates the possibility of chemical interaction between the materials in the different mattress components. Chemical interaction between different mattress components is especially a concern with many of the FR chemical compounds applied to fiber and foam in order to make those materials FR.

An example of a mattress with substantially uniform FR characteristic is shown in FIG. 1. The mattress 50 generally comprises a ticking 51 that surrounds various mattress components made up of a quilt panel 52, fill layers 54, 56, an insulator pad 40, a core 58, and a stabilizing layer 59. The ticking 51 is a decorative fabric that surrounds the mattress components. The quilt panel 52 is a high-loft nonwoven fiber batt quilted onto a woven or nonwoven quilt backing. The fill layers 54 and 56 are nonwoven fiber batts of various densities. The core 58 is a plurality of similarly oriented metal springs with optional fiberfill or other materials as discussed below. The stabilizing layer 59 is a densified nonwoven fiber batt. The insulator pad 40 is positioned adjacent to the upper surface of the core 58, between the core 58 and the fill layers 54 and 56. If desired, a second insulator pad (not shown), a second set of fill layers (not shown), and a second quilt layer (not shown) may be positioned adjacent to the lower surface of the core 58 instead of the stabilizing layer 59. The incorporation of the additional mattress components is advantageous because it gives the mattress a mirrored configuration from top to bottom. Such mattresses are considered “flipable” in that they provide the same amount of support to the user regardless of the side of the mattress that the user sleeps on.

The mattress 50 comprises a core 58 that includes at least one coiled metal wire. Most commonly, the coiled metal wire(s) are at least one compression spring, although other types of springs may be suitable for the purposes contemplated herein, which support the weight of a person sleeping on the mattress. Variously, the plural springs may be unconnected springs residing in a common space and configured for independent movement relative to one another, coupled to another by an interconnecting frame (not shown) and configured for independent movement relative to one another, or coupled to one another by the interconnecting frame and configured for common movement. It is further contemplated that the common space of the spring assembly may be filled with air, loose fibers (also known as fiberfill), high-loft or densified fiber batts, or other materials. In an embodiment, the metal springs of the core may be combined with a nonwoven synthetic fiber batt as described in U.S. Pat. No. 6,694,554 entitled “Fiber mass with side coil insertion”, assigned to the same entity as the present invention, and incorporated herein by reference as if reproduced in its entirety. If fiber material is used to fill the common space, such fiber material is consistent with the materials used in the other mattress components.

In an alternative embodiment, the core 58 may consist essentially of a densified nonwoven fiber batt. In the present embodiment, the core 58 consists essentially of synthetic fibers or a synthetic fiber blend formed into a densified nonwoven fiber batt and has a basis weight in ounces per square foot greater than the thickness in inches of the fiber batt. A densified fiber batt is preferable to a plurality of coil springs when it is preferable that the mattress not contain any metal components. Mattresses without metal components are required in many institutional settings, such as prisons, mental illness hospitals, and dormitories. Thus, it is often preferable that of the present invention that the cores 58 consists essentially of a densified nonwoven fiber batt and does not contain any metal springs.

The mattress 50 may also optionally comprise an insulator pad 40. The insulator pad 40 consists essentially of synthetic fibers or a synthetic fiber blend formed into a densified nonwoven fiber batt and has a basis weight in ounces per square foot greater than its thickness in inches of the nonwoven fiber batt. The insulator pad 40 is positioned between the metal springs of the core 58 and the fill layers 54, 56. The insulator pad 40 is sufficiently dense to maintain the separation between the core 58 and the fill layers 54, 56. The insulator pad 40 is optional because the core 58 may fulfill the separator function when it consists essentially of the densified fiber batt as described above.

The mattress 50 may also optionally comprise a stabilizing layer 59. The stabilizing layer 59 consists essentially of synthetic fibers or a synthetic fiber blend formed into a densified nonwoven fiber batt and has a basis weight in ounces per square foot greater than its thickness in inches of the nonwoven fiber batt. The stabilizing layer 59 is positioned between the lower surface of the metal springs of the core 58 and the ticking 51. The stabilizing layer 59 serves as a foundation for the core 58. In addition, the stabilization layer is sufficiently dense to maintain the separation between the core 58 and the ticking 51. The stabilizing layer 59 is optional when the core 58 consists essentially of the densified fiber batt, as described above.

The mattress 50 may also comprise a plurality of fill layers 54, 56. The fill layers 54, 56 comprise synthetic fibers or a synthetic fiber blend formed into a high-loft or densified non-woven fiber batts that cushion and support a person positioned atop the mattress. For example, the fill layers 54, 56 may be two or more layers of high-loft non-woven fiber batts arranged in such a manner that the densities of the individual fill layer 54, 56 form a density gradient with the most dense fill layer 56 on the bottom and the least dense fill layer 56 on the top. Of course, persons of ordinary skill in the art will appreciate that the individual fill layers 54, 56 may be arranged in any manner suitable for a particular application and that the present invention should not be limited to the specific embodiments disclosed herein. Persons of ordinary skill in the art will also appreciate that the plural fill layer 54, 56 may be replaced with an individual fill layer (not shown) having either a substantially uniform density or a density gradient oriented, for example, in the same orientation as the plural fill layers 54, 56 described above.

The mattress 50 may also comprise a quilt panel 52. The quilt panel 52 is a soft, cushioning layer typically positioned beneath the ticking 51. The quilt panel 52 comprises a quilt layer (not shown) attached to a quilt backing (not shown). The quilt layer comprises synthetic fibers or a synthetic fiber blend formed into a high-loft nonwoven fiber batt that is stitched, quilted, or other wise attached to the quilt backing. The quilt backing comprises synthetic fibers or a synthetic fiber blend formed into a thin, dense woven or nonwoven fabric with sufficient mechanical integrity to allow the quilt panel 52 to be manufactured, rolled, stored, unrolled, cut, and/or otherwise processed during the manufacture of the mattress 50. Of course, person of ordinary skill in the art will appreciate that the quilt panel 52 may comprise a single quilt layer and two quilt backings, such that the quilt layer is positioned between the two quilt backings. Persons of ordinary skill in the art will also appreciate that the quilt panel may be located on the exterior side of the mattress ticking 51, and is surrounded in its own ticking (not shown), which is commonly referred to as a pillow top configuration.

The mattress 50 may further comprise a ticking 51 that surrounds the quilt panel 52, the fill layers 54, 56, the insulator pad 40, the core 58, and the stabilizing layer 59. The ticking comprises synthetic fibers or a synthetic fiber blend formed into a lightweight woven or nonwoven fabric that is soft and flexible. The ticking 51 envelops the quilt panel 52, the fill layers 54, 56, the insulator pad 40, the core 58, and the stabilizing layer 59 and ensures that they remain positioned adjacent to one another and in a stationary position relative to one another.

The edges of the ticking 51 are joined together with a fabric tape (not shown) and thread (not shown). The thread comprises synthetic fibers or a synthetic fiber blend formed into a monofilament or multifilament line that may be optionally twisted and is used to stitch together two pieces of material. The tape comprises synthetic fibers or a synthetic fiber blend formed into a thin woven or nonwoven fabric used to wrap around the edges of the ticking 51 to prevent fraying. The tape may optionally contain an adhesive on one side.

The mattress components comprising the core 58, fill layers 54, 56, insulator pad 40, quilt panel 52, and ticking 51 described above consist essentially of synthetic fibers or a synthetic fiber blend formed into woven fabrics or high-loft or densified nonwoven fiber batts. The woven fabrics are formed by weaving the synthetic fibers with other synthetic fibers in a specific pattern, thereby producing a fabric. The nonwoven fiber batts may be high-loft nonwoven fiber batts, which are soft, resilient, compressible, and contain a plastic memory such that the batt yields to a compressive force, but returns to its original configurations upon removal of the compressive force. Alternatively, the nonwoven fiber batts may be densified fiber batts, which are hard, dense, non-resilient, and substantially incompressible. In one embodiment of the mattress with substantially uniform FR characteristic, the weight, density, and thickness of the various nonwoven fiber batts are determined by, among other factors, the process of compressing the batt during cooling, as discussed below. The ratio of batt density to batt thickness generally dictates whether a nonwoven fiber batt is a high loft batt or a densified batt. For purposes herein, a densified batt has a basis weight (in ounces per square foot of surface area) greater than the thickness (in inches). Thus, a densified fiber batt generally has a density greater than about 0.75 pounds per cubic foot (pcf). Conversely, a fiber batt having a basis weight (in ounces per square foot of surface area) less than the thickness (in inches) and/or a density less than about 0.75 pounds pcf are defined herein as high loft batts. High-loft batts also generally have at least about 90 percent air by volume and a thickness of at least 3 millimeters.

In an embodiment, the aforementioned components of the mattress with substantially uniform FR characteristic comprise a plurality of carrier fibers. The carrier fibers are preferably synthetic, but can be natural fibers if the natural fibers are treated to be made FR. For example, thermoplastic polymer fibers such as polyester or polypropylene are suitable synthetic carrier fibers. Other fibers can be used depending upon the precise processing limitations imposed and the characteristics of the batt which are desired at the end of the process. For purposes of illustrating the Mattress with substantially uniform FR characteristic and not by way of limitation, the carrier fiber may be a KoSa Type 209, 6 to 15 denier, 2 to 3 inches in length, round hollow cross section polyester fiber. Alternatively, the carrier fiber may be a KoSa Type 295, 6 to 15 denier, ⅕ to 4 inches in length, pentalobal cross section polyester fiber. Other types of fibers are suitable as carrier fibers for the present invention and are within the scope of this invention.

In an embodiment, the components of the mattress with substantially uniform FR characteristic comprise a homogeneous blend of binder fibers and carrier fibers. As with the carrier fibers, the binder fibers are preferably synthetic, such a polyester or polypropylene. The binder fiber has a relatively low predetermined melting temperature as compared with the carrier fiber. As used herein, however, the term melting does not necessarily refer only to the actual transformation of the solid binder fibers into liquid form. Rather, it includes a gradual transformation of the fibers or, in the case of a bicomponent sheath/core fiber, the sheath of the fiber, over a range of temperatures within which the sheath becomes sufficiently soft and tacky to cling to other fibers within which it comes in contact, including other binder fibers having its same characteristics and, as described above, adjacent carrier fibers having a higher melting temperature. It is an inherent characteristic of thermoplastic fibers such as polyester that they become sticky and tacky when melted, as that term is used herein. For purposes of illustrating the mattress with substantially uniform FR characteristic and not by way of limitation, the binder fiber may be a Type 254 Celbond® fiber available from KoSa which is a bicomponent fiber with a polyester core and a copolyester sheath. The sheath component melting temperature is approximately 230° F. (110° C.). The binder fiber, alternatively, can be a polyester copolymer rather than a bicomponent fiber.

While the homogeneous mixture of carrier fibers and binder fibers can be any of a number of suitable fiber blends, for purposes of illustrating the mattress with substantially uniform FR characteristic, the mixture is comprised of binder finders in an amount sufficient for binding the fibers of the blend together upon application of heat at the appropriate temperature to melt the binder fibers. In one example, the binder fibers are in the range of about 5 percent to about 100 percent by total volume of the blend. Preferably, the binder finders are present in the range of about 10 percent to about 15 percent for a high-loft batt and in the range of about 15 percent to about 40 percent for a densified batt, as those characteristics are discussed below. The carrier fibers in the remaining blend volume ranges anywhere from about 0 percent to about 95 percent. Preferably, the carrier finders are present in the range of about 85 percent to about 90 percent for a high-loft batt and in the range of about 60 percent to about 85 percent for a densified batt, as those characteristics are discussed below. Blends having other percentages of binder fibers and carrier fibers are also within the scope of the invention.

In yet another embodiment of the invention, the carrier and binder fibers described herein can be blended with a plurality of FR fibers. The FR fibers are fibers that resist burning, impede the propagation of a fire, reduce the ignitability of the volatile gases produced during burning, and/or help to extinguish the fire. The FR fibers may be fibers that are inherently FR, such as charring fibers, or fibers that have been chemically treated to become FR, such as fibers treated with a FR chemical compound. Examples of FR fibers are fully or partially oxidized polyacrylonitriles (O-PAN) such as PYRON® available from Zoltek, FORTAFIL® available from Fortafil Fibers, AVOX™ available from Textron, PANOX® available from SGL Technik, THORNEL® available from Amoco Performance Products, and PYROMEX® available from Toho Texax; meta-aramids, such as NOMEX® available from DuPont, TEUINCONEX™ available from Teijin Limited, and FENYLENE™ available from Russian State Complex, including poly(m-phenylene isophthalamide); para-aramids such as KEVLAR® available from DuPont, TECHNORA® available from Teijin Limited, TWARON® available from Teijin Twaron, and FENYLENE™ available from the Russian State Complex, including poly(p-phenylene terephthalamide) and poly(diphenylether para-aramid); melamines such as BASOFIL® available from Basofil Fibers; polybenzimidazole; poly (p-phenylene benzobisoxazoles); polyetherimides; polybenzimidazole such as PBI® by Hoechst Celanese; polyimides such as P-84™ by Inspec Fibers and KAPTON® by DuPont; polyamideimides such as KERMEL® by Kermel; novoloids such as phenol-formaldehyde novolac and KYNOL™ available from Gun Ei Chemical Industry; poly(p-phenylene benzobisoxazole) (PBO) such as ZYLON® available from Toyobo; poly (p-phenylene benzothiazoles) (PBT); polyphenylene sulfide (PPS) such as RYTON® available from Chevron Phillips Chemical, TORAY® PPS available from Toray Industries, FORTRON® available from Hoechst Celanese, and PROCON™ available from Toyobo; flame retardant viscose rayons, such as LENZING® FR by Lenzing and VISIL® by Steri Oy; polyetheretherketones (PEEK) such as ZYEX® available from Zyex Ltd.; polyketones (PEK) such as ULTRAPEK™ available from BASF; polyetherimides (PEI) such as ULTEM® available from General Electric; and combinations thereof.

FR fibers may also be fibers that release oxygen depleting gasses to substantially reduce or eliminate the ignitability of the volatile gases produced during burning and help to extinguish the fire. Examples of these FR fibers are: chloropolymeric fibers, such as those containing polyvinyl chloride (PVC) or polyvinylidene homopolymers and copolymers, such as THERMOVYL™, FIBRAVYL™, RETRACTYL™, and ISOVYL™ available from Rhovyl; PIVIACID™ available from Thueringische; VICLON™ available from Kureha Chemical Industry, TEVIRON® available from Teijin Ltd., ENVILON® available from Toyo Chemical, and VICRON™ made in Korea; SARAN™ available from Pittsfield Weaving, KREHALON™ available from Kureha Chemical Industry, and OMNI-SARAN™ available from Fibrasomni; and modacrylics which are vinyl chloride or vinylidene chloride copolymer variants of acrylonitrile fibers, such as PROTEX® available from Kanegafuchi Chemical and SEF® available from Solutia; and combinations thereof. Further examples of these FR fibers are Fluoropolymeric fibers such as polytetrafluoroethylene (PTFE), such as TEFLON® available from DuPont, LENZING™ available from Lenzing, RASTEX® available from W. R. Gore and Associates, GORE-TEX® available from W. R. Gore and Associates, PROFILEN® available from Lenzing, and TOYOFLON® available from Toray Industries; poly(ethylene-chlorotriflu-oroethylene) (E-CTFE) such as HALAR® available from Ausimont and TOYOFLON® available from Toray Industries, polyvinylidene fluoride (PVDF) such as KYNAR® available from Arkema, and FLORLON™ available from Russian State Complex; polyperfluoroalkoxy (PFA) such as TEFLON® available from DuPont and TOYOFLON® available from Toray Industries, polyfluorinated ethylene-propylene (FEP) such as TEFLON® FEP available from DuPont; and combinations thereof. The incorporation of FR fibers into a blend of carrier fibers and binder fibers is described in U.S. patent application Ser. No. 10/968,339 entitled “Fire Resistant Nonwoven Batt Having Both Charring and Oxygen Depleting Fibers”, filed Oct. 18, 2004, and U.S. patent application Ser. No. 11/088,658 entitled “Gray Fire Resistant Nonwoven Batt Formed From A Blend Of Fire Retardant Materials And An Associated Method Of Manufacturing The Same”, filed Mar. 23, 2005, both of which are assigned to same assignee as the present invention and both of which are incorporated herein by reference, including any underlying provisional or non provisional applications, as if reproduced in their entirety.

One method for making a high-loft fiber batt will now be described in further detail. As seen in FIG. 2, method 70 for making the high-loft nonwoven fiber batt generally comprises: blending the fibers at 72, forming the fibers into a web at 74, compressing the web at 76, heating the web to form a batt at 78, and cooling the batt at 80. The high-loft nonwoven fiber batt formed by method 70 may be used as one or more of the core filling (if applicable), the fill layers 54, 56, quilt backing, and/or the quilt layer.

Referring now to FIG. 3, a schematic top plan view of a processing line 110 for constructing the high-loft nonwoven fiber batt in accordance with the teachings of the present invention will now be described in greater detail. If applicable, the carrier fibers and binder fibers are blended together per 72 of method 70 in a fiber blender 112 and conveyed by conveyor pipes 114 to a web-forming machine or, in this example, three machines 116, 117, and 118. The fibers are preferably a blend of carrier fibers, such as polyester, and binder fibers, such as sheath-core bicomponent fibers, but may be a blend of any binder fibers and any carrier fibers or may be a specific type of synthetic fiber. A suitable web-forming machine is a Garnett machine. An air laying machine, known in the trade as a Rando webber, or any other suitable apparatus can also be used to form a web structure. Garnett machines 116, 117, and 118 card the blended fibers into a web per 74 of method 70 and deliver the web to cross-lappers 116′, 117′, and 118′ to cross-lap the web onto a slat conveyor 120 which is moving in the machine direction. Cross-lappers 116′, 117′, and 118′ reciprocate back and forth in the cross direction from one side of conveyor 120 to the other side to form the web having multiple thicknesses in a progressive overlapping relationship. The number of layers that make up the web is determined by the speed of the conveyor 120 in relation to the speed at which successive layers of the web are layered on top of each other and the number of cross-lappers 116′, 117′, and 118′. Thus, the number of single layers which make up the web can be increased by slowing the relative speed of the conveyor 120 in relation to the speed at which cross layers are layered, by increasing the number of cross-lappers 116′, 117′, and 118′, or both. Conversely, a fewer number of single layers can be achieved by increasing the relative speed of conveyor 120 to the speed of laying the cross layers, by decreasing the number of cross-lappers 116′, 117′, and 118′, or both. In the present invention, the number of single layers which make up the web of fibers vary depending on the desired characteristics of the high-loft nonwoven fiber batt of the present invention. As a result, the relative speed of the conveyor 120 to the speed at which cross layers are layered and the number of cross-lappers 116′, 117′, and 118′ for forming the web may vary accordingly.

The conveyor 120 then transports the web to housing 130 for mechanical and/or vacuum compression per 76 of method 70 and heating per 78 of method 70. While there are a variety of thermal bonding methods which are suitable for the purposes contemplated herein, one such method the application of vacuum pressure through perforations (not shown) in first and second counter rotating drums 140 and 142 positioned in a central portion of the housing 130. The first and second counter rotating drums 140 and 142 heat the web to the extent necessary to melt the binder fibers in the web. For example, heating the web to a temperature of 225-275° F. for a period of three to five minutes is suitable for the purposes contemplated herein. Alternatively, the web may instead move through an oven by substantially parallel perforated or mesh wire aprons that mechanically compress the batt and simultaneously melt the binder fibers.

As the web exits the housing 130, the web is compressed and cooled per 80 of method 70 using a pair of substantially parallel wire mesh aprons 170, only one of which is visible in FIG. 3. The aprons 170 are mounted for parallel movement relative to each other to facilitate adjustment for a wide range of web thicknesses. The web can be cooled slowly through exposure to ambient temperature air or, in the alternative, ambient temperature air can be forced through the perforations of one apron 170, through the web and through the perforations of the other apron 172 from FIG. 6A to cool the web and set it in its compressed state. The web is maintained in its compressed form upon cooling since the solidification of the binder fibers bonds the fibers together in that state.

While there are a variety of thermal bonding methods which are suitable for the present invention, one such method, illustrated in FIG. 4A, comprises holding the web by vacuum pressure applied through perforations of first and second counter-rotating drums and heating the web so that the binder fibers in the batt melt to the extent necessary to fuse together the fibers in the web. Alternatively, the web moves through an oven by substantially parallel perforated or mesh wire aprons to melt the binder fibers.

As may be seen in FIG. 4A, the aforementioned vacuum pressure method may be implemented using counter-rotating drums 140, 142 having perforations 141, 143, respectively, which are positioned in a central portion of a housing 130. The housing 130 also comprises an air circulation chamber 132 and a furnace 134 in an upper portion and a lower portion, respectively, thereof. The drum 140 is positioned adjacent an inlet 144 though which the web is fed. The web is delivered from the blending and web-forming processes described herein by means of an infeed apron 146. A suction fan 150 is positioned in communication with the interior of the drum 140. The lower portion of the circumference of the drum 140 is shielded by a baffle 151 positioned inside the drum 140 such that the suction-creating air flow is forced to enter the drum 140 through the perforations 141, which are proximate the upper portion of the drum 140, as the drum 140 rotates.

The drum 142 is downstream from the drum 140 in the housing 130. The drums 140, 142 can be mounted for lateral sliding movement relative to one another to facilitate adjustment for a wide range of batt thicknesses (not shown). The drum 142 includes a suction fan 152 that is positioned in communication with the interior of the drum 142. The upper portion of the circumference of the drum 142 is shielded by a baffle 153 positioned inside the drum 142 so that the suction-creating air flow is forced to enter the drum 142 through the perforations 143, which are proximate the lower portion of drum 142, as the drum 142 rotates.

The nonwoven web is held in vacuum pressure as it moves from the upper portion of the rotating drum 140 to the lower portion of the counter rotating drum 142. The furnace 134 heats the air in the housing 130 as it flows from the perforations 141, 143 to the interior of the drums 140, 142, respectively, to melt the binder fibers in the web to the extent necessary to bind together the fibers in the web.

Referring to FIG. 4B, in an alternative thermal bonding process, the web enters housing 130′ by a pair of substantially parallel perforated or mesh wire aprons 160, 162. The housing 130′ comprises an oven 134′ that heats the web to melt the binder fibers to the extent necessary to bind the fibers in the web together.

Collectively referring back to FIGS. 2, 3, 4A and 4B, the web is compressed and cooled per 80 of method 70 as it exits from the housing 130 or 130′ by a pair of substantially parallel first and second perforated or wire mesh aprons 170 and 172 or 160 and 162. The aprons 170 and 172 or 160 and 162 are mounted for parallel movement relative to each other to facilitate adjustment for a wide range of web thicknesses (not shown). The web can be cooled slowly through exposure to ambient temperature air or, alternatively, ambient temperature air can be forced through the perforations of one apron, through the web and through the perforations of the other apron to cool the web and set it in its compressed state. The web is maintained in its compressed form upon cooling since the binder fibers bonds the fibers together in the compressed state. The cooled web (which, after completion of the bonding, compression and cooling, is referred to as a batt) moves into cutting zone 180 where the lateral edges of the batt are trimmed to a finished width. The batt is then cut transversely to a desired length to form the high-loft nonwoven fiber batt.

One method for making the densified nonwoven fiber batt will now be described in greater detail. As seen in FIG. 5, a method 190 for making the nonwoven fiber batt embodiment of the densified nonwoven fiber batt commences at 191 where the synthetic fibers are blended to form a homogeneous fiber blend. Proceeding on to 192, a web is formed from the fibers of the homogeneous fiber blend. At 193, the web is coated with a resin, and then the web is subsequently needle punched at 194. The web is then compressed in 195 and heated at 196 to form a nonwoven fiber batt. The nonwoven fiber batt is subsequently cooled at 197 and trimmed at 198, thereby forming the densified nonwoven fiber batt. Each of these steps is described in greater detail below.

FIG. 6 illustrates the schematic top plan view of the general processing line 110 from FIG. 3, but modified to construct a densified nonwoven fiber batt in accordance with the teachings of the present invention. The general processing line 110 shown in FIG. 6 performs steps 191 through 197 of method 190. Steps 191, 192, 195, 196 and 197 of method 190 are similar to steps 72 to 80 of method 70 and are performed in a similar manner to that described above in relation to high-loft nonwoven fiber batts and need not be repeated here. A notable exception is that the method 190 generally does not require binder fibers, so the binder fibers are typically excluded form the common fiber composition when forming the densified fiber batt. The additional steps 193 and 194 of method 190 are performed by resin applicator 122 and needle loom 124, both of which are discussed below.

A heat curable resin is then applied to the web by resin applicator 122 per 193 of method 190. There are a variety of techniques suitable for applying resins onto the web. For example, liquid resin may be sprayed or froth resin extruded onto the web. Resins suitable for the present invention are curable by heat and can be any of a variety of compositions. Generally, the resin is comprised of polyvinyl acetate but may also be a polymeric composition such as vinylidene chloride copolymer, latex, acrylic, or any other chemical compound. An example of a suitable resin is the SARAN™ 506 resin available from the Dow Chemical Company. Additionally, the resin can contain antimicrobial, antifungal, or hydrophobic additives that further enhance the properties of the densified nonwoven fiber batt.

Further describing the application of liquid resin, as the web moves along a conveyor in the machine direction, the resin is sprayed onto the web from one or more spray heads that move in a transverse or cross direction to substantially coat the web. Alternatively, froth resin can be extruded onto the web using a knife or other means. The web can also be fed through or dipped into a resin bath. The applied resin is crushed into the web for saturation therethrough by nip rollers disposed along the transverse direction of the conveyor to apply pressure to the surface of the batt. Alternatively, the resin is crushed into the web by vacuum pressure applied through the batt.

The web then moves to a needle loom 124 where the web is needle-punched per 194 of method 190 to increase the density of the web. The needle loom 124 is a device that bonds a nonwoven web by mechanically entangling the fibers within the web. The needle loom 124 contains a needle board (not shown) that contains a plurality of downwardly-facing barbed needles arranged in a non-aligned pattern. The barbs on the needles are arranged such that they capture fibers when the needle is pressed into the web, but do not capture any fibers when the needle is removed from the web. A variety of suitable needles are available from the Foster Needle Company. The use of the needle loom in the present invention provides mechanical compression of the web prior to the application of heat in combination with either vacuum and/or mechanical compression within housing 130. Of course, it is within the scope of the invention to forego the needle punching described herein if adequate compression can be obtained by vacuum and/or mechanical compression. Likewise, it is within the scope of the invention to forego the vacuum and/or mechanical compression if adequate compression can be obtained by needle punching.

When all of the mattress components have been manufactured, the mattress is assembled in a conventional manner such as, for example, layering the mattress components on top of one another, and then covering the layered mattress components with the ticking. If desired, the various mattress layers may be adhered, stitched, or otherwise joined together. Typically, two pieces of ticking 51 are joined together by positioning the edges of the two pieces of ticking 51 next to each other such that they have a common edge, and then the tape is wrapped around the common edge such that the tape fully covers the edge of each individual piece of ticking. The thread is then positioned within a needle used to stitch the tape and the two pieces of ticking 51 together, thereby creating a seam. If desired, the finished mattress may be stitched together in a decorative pattern.

While a number of preferred embodiments of the invention have been shown and described herein, modifications thereof may be made by one skilled in the art without departing from the spirit and the teachings of the invention. The embodiments described herein are exemplary only, and are not intended to be limiting. Many variations, combinations, and modifications of the invention disclosed herein are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited by the description set out above, but is defined by the claims which follow, that scope including all equivalents of the subject matter of the claims. 

1. A fire resistant (FR) mattress comprising: a core comprising a first densified nonwoven fiber batt; and a ticking comprising a first fabric, the ticking enclosing the core and the fill layer; wherein the core and the ticking consist essentially of a common fiber composition having substantially identical FR characteristic, thereby imparting the substantially uniform FR characteristic upon the mattress.
 2. The mattress of claim 1 further comprising: a fill layer comprising a first high-loft nonwoven fiber batt, the fill layer positioned between the core and the ticking; and wherein the core, the fill layer, and the ticking consist essentially of a common fiber composition having substantially identical FR characteristic, thereby imparting the substantially uniform FR characteristic upon the mattress.
 3. The mattress of claim 2 wherein the common fiber composition consists essentially of synthetic fibers.
 4. The mattress of claim 3 wherein the mattress further comprises a plurality of similarly oriented spring coils arranged in a common plane within the core.
 5. The mattress of claim 4 wherein a coil spring path is adjacent to each of the spring coils in the core.
 6. The mattress of claim 5 further comprising an insulator pad comprised of a second densified nonwoven fiber batt consisting essentially of the common fiber composition, the insulator pad positioned between the core and the fill layer such that the insulator pad separates the core from the fill layer.
 7. The mattress of claim 6 further comprising: a quilt panel positioned above the fill layer, the quilt panel comprising: a quilt backing comprised a second fabric consisting essentially of the common fiber composition; and a quilt layer comprised a second high-loft nonwoven fiber batt consisting essentially of the common fiber composition.
 8. The mattress of claim 7 further comprising: a tape comprised of a third fabric consisting essentially of the common fiber composition; and a thread comprising at least one filament consisting essentially of the common fiber composition; wherein the tape and the thread join the edges of the ticking together, thereby creating a seam.
 9. The mattress of claim 8 wherein the core, the insulator pad, the fill layer, the ticking, the quilt panel, the tape, and the thread are fire resistant.
 10. The mattress of claim 9 wherein the core, the insulator pad, the fill layer, the ticking, the quilt panel, the tape, and the thread are substantially free of fiberglass.
 11. The mattress of claim 10 wherein the common fiber composition consists essentially of fibers selected from the group consisting of: polyester and polypropylene.
 12. A mattress comprising: a core; a plurality of substantially adjacent similarly oriented spring coils arranged in a common plane within the core; and a ticking comprising a first fabric, the ticking enclosing the core and the fill layer; wherein the core and the ticking consist essentially of a common fiber composition having substantially identical FR characteristic, thereby imparting the substantially uniform FR characteristic upon the mattress.
 13. The mattress of claim 12 further comprising: a fill layer comprising a first high-loft nonwoven fiber batt, the fill layer positioned between the core and the ticking; and wherein the core, the fill layer, and the ticking consist essentially of a common fiber composition having substantially identical FR characteristic, thereby imparting the substantially uniform FR characteristic upon the mattress.
 14. The mattress of claim 13 wherein the common fiber composition consists essentially of synthetic fibers.
 15. The mattress of claim 14 wherein the core further comprises a first densified nonwoven fiber batt.
 16. The mattress of claim 15 wherein a coil spring path is adjacent to each of the spring coils in the core.
 17. The mattress of claim 16 further comprising an insulator pad comprised of a second densified nonwoven fiber batt consisting essentially of the common fiber composition, the insulator pad positioned between the core and the fill layer such that the insulator pad separates the core from the fill layer.
 18. The mattress of claim 17 further comprising: a quilt panel positioned above the fill layer, the quilt panel comprising: a quilt backing comprised a second fabric consisting essentially of the common fiber composition; and a quilt layer comprised a second high-loft nonwoven fiber batt consisting essentially of the common fiber composition.
 19. The mattress of claim 18 further comprising: a tape comprised of a third fabric consisting essentially of the common fiber composition; and a thread comprising at least one filament consisting essentially of the common fiber composition; wherein the tape and the thread join the edges of the ticking together, thereby creating a seam.
 20. A mattress comprising: a core; a plurality of substantially adjacent similarly oriented spring coils arranged in a common plane within the core; a fill layer comprising a first high-loft nonwoven fiber batt, the fill layer positioned above the core; an insulator pad comprised of a first densified nonwoven fiber batt, the insulator pad positioned between the core and the fill layer such that the insulator pad separates the core from the fill layer; a ticking comprising a first fabric, the ticking enclosing the core, the insulator pad, and the fill layer; a quilt panel positioned above the fill layer, the quilt panel comprising: a quilt backing comprised a second fabric; and a quilt layer comprised a second high-loft nonwoven fiber batt; a tape comprised of a third fabric consisting essentially of the common fiber composition; and a thread comprising at least one filament consisting essentially of the common fiber composition; wherein the tape and the thread join the edges of the ticking together, thereby creating a seam; and wherein the core, the fill layer, the insulator pad, the quilt backing, the quilt layer, the tape, the thread, and the ticking consist essentially of a common fiber composition having substantially identical FR characteristic, thereby imparting the substantially uniform FR characteristic upon the mattress. 